WO2011064406A1

WO2011064406A1 - Method for making a metal reinforcement for a turbine engine blade

Info

Publication number: WO2011064406A1
Application number: PCT/EP2010/068578
Authority: WO
Inventors: Bernard José Michel CATTIEZ; Thierry Jean Emile Flesch; Jérôme GUINOIS; Stéphane André Leveque; Philippe Marolle
Original assignee: Snecma
Priority date: 2009-11-30
Filing date: 2010-11-30
Publication date: 2011-06-03
Also published as: EP2507010B1; EP2998062A1; RU2012127372A; CN102639287A; EP2507010A1; US20120233859A1; CA2781679A1; JP2013513055A; BR112012013064A2

Abstract

The present invention relates to a method for making a metal reinforcement (30) for the leading edge or trailing edge of a turbine engine blade, comprising in sequence: a step (44) for positioning a preform (26, 70) by means of equipment (60) positioning said preform (26, 70) in a position such that said preform (26, 70), at one end thereof, has an area (28, 72) which is capable of receiving a filler metal; and a step (46) for constructing a base (39) for said metal reinforcement (30) by hard-surfacing with filler metal in said area (28), in the form of metal beads.

Description

PROCESS FOR PRODUCING A TURBOMACHINE TURBINE METAL REINFORCEMENT

The present invention relates to a method for producing a metallic blade reinforcement composite or metal turbomachine.

More particularly, the invention relates to a method for producing a turbomachine blade leading edge metal reinforcement.

The field of the invention is that of turbomachines and more particularly that of the fan blades, made of composite or metallic material, of a turbomachine and whose leading edge comprises a metallic structural reinforcement.

However, the invention is also applicable to the production of a metal reinforcement intended to reinforce a turbomachine blade trailing edge.

It is recalled that the leading edge corresponds to the front part of an airfoil which faces the airflow and which divides the airflow into an intrados airflow and a flow of air. extrados air. The trailing edge corresponds to the posterior part of an aerodynamic profile where the intrados and extrados flows meet.

It is known to equip the fan blades of a turbomachine, made of composite materials, with a metallic structural reinforcement extending over the entire height of the blade and beyond their leading edge as mentioned in FIG. EP1908919. Such a reinforcement makes it possible to protect the composite blading during an impact of a foreign body on the blower, such as, for example, a bird, hail or pebbles.

In particular, the metal structural reinforcement protects the leading edge of the composite blade by avoiding risks of delamination, fiber breakage or damage by fiber / matrix decohesion.

Conventionally, a turbomachine blade has a surface aerodynamic device extending in a first direction between a leading edge and a trailing edge and, in a second direction substantially perpendicular to the first direction, between a foot and an apex of the blade. The metallic structural reinforcement follows the shape of the leading edge of the aerodynamic surface of the blade and extends in the first direction beyond the leading edge of the aerodynamic surface of the blade to match the profile of the blade. the intrados and the upper surface of the dawn and in the second direction between the foot and the top of the dawn.

In known manner, the metallic structural reinforcement is a metal part made entirely by milling from a block of material.

Another embodiment of such a metal structural reinforcement is described in particular in the document FR2319008.

However, the metal reinforcement of a blade leading edge is a complex piece to achieve, requiring many rework operations and complex tools involving significant realization costs.

In this context, the invention aims to solve the problems mentioned above by proposing a method for producing a leading edge metal reinforcement or turbomachine blade trailing edge to significantly reduce the costs of production. of such a piece and to simplify the manufacturing range.

To this end, the invention proposes a method for producing a leading edge metal reinforcement or turbomachine blade trailing edge edge successively comprising:

a step of positioning a preform by means of a tooling positioning said preform in a position such that said preform has at one end a zone capable of receiving filler metal;

a step of constructing a base of said metal reinforcement by reloading filler metal in said area, in the form of metal beads.

Thanks to the invention, the metallic structural reinforcement is made simply and quickly from a preform and a method of material reconstruction by MIG welding (for "Metal Inert Gas") building the base of the reinforcement from end of the preform implemented in a maintenance tool and conformation. Preferably, the MIG process used is an improvement called CMT (Cold Metal Transfer) which is described in the application FR0802986. This particular process makes it possible to deposit large volumes of material while minimizing the deformation of the sheets.

This production method thus makes it possible to dispense with the complex implementation of the reinforcement by milling in the mass from flats requiring large volume of processing material and therefore significant costs in raw material supply.

The method according to the invention also makes it possible to substantially reduce the manufacturing costs of such a part.

Advantageously, the preform is formed by a first metal sheet and a second metal sheet positioned in the tool so that they have at their end a seam capable of receiving the welding material.

The method for producing a turbomachine blade metal reinforcement according to the invention may also have one or more of the following characteristics, considered individually or in any technically possible combination:

said step of building by reloading of filler metal is carried out by means of a MIG welding apparatus comprising a pulsed current generator and presenting a flow rate of pulsed filler wire; said preform comprises a first metal sheet and a second metal sheet positioned, by means of said tooling, in a non-parallel position so that they have at their end an area capable of receiving said filler metal, said step of constructing said base of said reinforcement solidarisant said metal sheets in position;

- Said preform is formed by a hot preformed metal sheet so that said preform has flanks and at one end an area adapted to receive said filler metal. ;

said construction step is followed by a step of machining said material reloaded in said welding zone so as to approach the final profile of said base;

the method comprises a stress relaxation heat treatment step;

the process comprises a hot conformation step;

the method comprises a step of finishing said metal reinforcement consisting in the recovery of said recharged material so as to refine the final profile of said base and the leading edge or the trailing edge of said metal reinforcement and / or in the recovery of metal sheets so as to form the flanks of said metal reinforcement;

the method comprises a step of cutting said first metal sheet and said second metal sheet by laser cutting;

- The method comprises an operation of increasing the roughness of the inner faces of said flanks;

the method comprises a step of shaping said metal sheets before said step of positioning in said tooling;

during said positioning step, said metal sheets are shaped in said tooling and are held together;

during said positioning step, said metal sheets are shaped and held spaced apart by a dagger positioned between said metal sheets, the outer profile of said dagger conforming the profile of the intrados and extrados said metal sheets;

the method comprises a step of evacuating heat from said metal sheets in position in said tooling via said tooling. Other characteristics and advantages of the invention will emerge more clearly from the description which is given below, by way of indication and in no way limiting, with reference to the appended figures, in which: FIG. 1 is a side view of a blade comprising a metal structural reinforcement of the leading edge obtained by means of the embodiment method according to the invention;

- Figure 2 is a partial sectional view of Figure 1 along a cutting plane AA;

FIG. 3 is a block diagram showing the main steps for producing a turbomachine blade leading edge metallic structural reinforcement of the embodiment method according to the invention;

- Figure 4 is a partial sectional view of the turbomachine blade leading edge metal reinforcement in a first embodiment of the third step of the method illustrated in Figure 3;

- Figure 5 is a partial sectional view of the turbomachine blade leading edge metal reinforcement in a second embodiment of the third step of the method illustrated in Figure 3;

FIG. 6 is a partial sectional view of the turbomachine blade leading edge metal reinforcement during the fourth step of the process illustrated in FIG. 3;

FIG. 7 is a partial sectional view of the turbomachine blade leading edge metal reinforcement during a fifth step of the process illustrated in FIG. 3; - Figure 8 is a partial sectional view of the turbomachine blade leading edge metal reinforcement in its final state obtained by the embodiment of the invention illustrated in Figure 3;

FIG. 9 illustrates an exploded view of the specific holding tooling used for producing the leading edge metal reinforcement according to the embodiment method illustrated in FIG. 3;

FIG. 10 illustrates a view of the turbomachine blade leading edge metal reinforcement in its initial state in a second embodiment of a preform according to the embodiment method illustrated in FIG. 3:

FIG. 11 illustrates a view of the turbomachine blade leading edge metal reinforcement in its final state in a second embodiment of a preform according to the embodiment method illustrated in FIG. 3.

FIG. 12 is a block diagram showing the main steps for producing a turbomachine blade leading edge metal structural reinforcement of a second method of producing a metal reinforcement;

FIG. 13 is a view of the turbomachine blade leading edge metal reinforcement during the first step of the second embodiment illustrated in FIG. 12;

FIG. 14 is a view of the turbomachine blade leading edge metal reinforcement during the second step of the second embodiment illustrated in FIG. 12;

FIG. 15a is a side view of the turbomachine blade leading edge metal reinforcement during the third step of the econd process of embodiment illustrated in FIG. 12;

FIG. 15b is a sectional view of the turbomachine blade leading edge metal reinforcement illustrated in FIG. 15a according to the plan CC cutter;

FIG. 16 is a front view of the turbomachine blade leading edge metal reinforcement during the fourth step of the second embodiment illustrated in FIG. 12;

FIG. 17 is a front view of the turbomachine blade leading edge metal reinforcement during the fifth step of the second embodiment illustrated in FIG. 12;

FIG. 18 is a view of the turbomachine blade leading edge metal reinforcement during the sixth step of the second embodiment illustrated in FIG. 12;

FIG. 19 is a front view of the turbomachine blade leading edge metal reinforcement during the seventh step of the second embodiment illustrated in FIG. 12;

- Figure 20 is a side view of the turbomachine blade leading edge metal reinforcement in its final state obtained by the second embodiment illustrated in Figure 12;

FIG. 21 is a cross-sectional view of the specific holding tooling used for producing the leading edge metal reinforcement according to the second embodiment method illustrated in FIG. 12. In all the figures, the common elements bear the same reference numbers unless otherwise specified.

FIG. 1 is a side view of a blade comprising a metallic leading edge structural reinforcement obtained by means of the embodiment method according to the invention.

The blade 10 illustrated is for example a mobile blade of a fan of a turbomachine (not shown).

The blade 10 has an aerodynamic surface 12 extending in a first axial direction 14 between a leading edge 16 and a trailing edge 18 and in a second radial direction 20 substantially perpendicular to the first direction 14 between a foot 22 and a vertex 24.

The aerodynamic surface 12 forms the extrados face 13 and intrados 1 1 of the blade 10, only the extrados face 13 of the blade 10 is shown in Figure 1. The intrados 11 and the extrados 13 form the lateral faces of the blade 10 which connect the leading edge 16 to the trailing edge 18 of the blade 10.

In this embodiment, the blade 10 is a composite blade typically obtained by draping a woven composite material. By way of example, the composite material used may be composed of an assembly of woven carbon fibers and a resinous matrix, the assembly being formed by molding using a vacuum resin injection method of RTM (for "Resin Transfer Molding").

The blade 10 has a metal structural reinforcement 30 bonded at its leading edge 16 and which extends both in the first direction 14 beyond the leading edge 16 of the aerodynamic surface 12 of the blade. dawn 10 and in the second direction 20 between the foot 22 and the apex 24 of the dawn.

As represented in FIG. 2, the structural reinforcement 30 matches the shape of the leading edge 16 of the aerodynamic surface 12 of the blade 10 that it extends to form a leading edge 31, said leading edge of the reinforcement .

Conventionally, the structural reinforcement 30 is a one-piece piece having a substantially V-shaped section having a base 39 forming the leading edge 31 and extended by two lateral flanks 35 and 37 respectively fitting the intrados 11 and extrados 13 the aerodynamic surface 12 of the dawn. Flanks 35, 37 have a tapered or thinned profile towards the trailing edge of the blade.

The base 39 has a rounded internal profile 33 capable of conforming to the rounded shape of the leading edge 16 of the blade 10.

The structural reinforcement 30 is metallic and preferably based on titanium. This material has a high absorption capacity of energy due to shocks. The reinforcement is glued on the blade 10 by means of adhesive known to those skilled in the art, such as a cyanoacrylic or epoxy glue.

This type of metal structural reinforcement 30 used for the turbomachine composite blade reinforcement is more particularly described in particular in the patent application EP1908919.

The method according to the invention makes it possible to carry out a structural reinforcement as illustrated in FIG. 2, FIG. 2 illustrating the reinforcement 30 in its final state.

FIG. 3 represents a block diagram illustrating the main steps of a method for producing a blade blade leading edge metal structural reinforcement 10 as illustrated in FIGS. 1 and 2. The first step 40 of the method Embodiment 100 is a step of cutting flat sheets. The first step 40 comprises a first sub-step 43 for cutting a first flat sheet and a second sub-stage 45 for cutting a second flat sheet.

The flat sheets are cut by a cutting method known to those skilled in the art for cutting sheets of small thickness, that is to say of the order of a few millimeters. By way of example, the cutting method may be a laser cutting method.

The two cut sheets will allow to realize the two flanks

35, 37 of the metal reinforcement 30.

The second step 42 of the embodiment method 100 is a step of shaping cut edges 35, 37. The conformation is carried out by compressive stressing of the extrados face of each flank 35, 37. This first shaping is non-permanent and allows a certain curve to be given to each flank, in particular the shape of an intrados and dia. 'an extrados. The curve of the flanks helps to position the flanks 35, 37 during the next positioning step. For example, this compression can be achieved by a burnishing process or hammering. This step may also include an operation to increase the roughness of the inner faces of the sidewalls 35, 37 to facilitate the attachment of the reinforcement 30 on the blade 10 but also to increase the adhesion of the sidewalls 35, 37 in the specific tooling of maintenance during the next positioning step.

The third step 44 of the embodiment method 100 is a step of positioning, or docking, two flanks 35, 37 cut. The two flanks 35, 37 are positioned in a specific holding tool 60 so that the two flanks 35, 37 have a common area in contact or that the two flanks 35, 37 are separated by a distance defined by the tool, the two sides 35, 37 forming a preform 26 of the metal reinforcement 30.

Figures 4 and 5 respectively show two embodiments of this third step 44 of the production method.

FIG. 4 shows more particularly a first embodiment in which the two sidewalls 35, 37 are contiguous and have a common contact zone 36.

In this embodiment and preferably, the flanks 35 and 37 have, at their end close to the contact zone 36, a curvature obtained during the second forming step 42 for simplifying the contacting of the flanks 35, 37.

FIG. 5 more particularly represents a second embodiment in which the two ends of the flanks 35, 37 are separated by a defined distance, the distance separating the two flanks 35, 37 being determined by the tooling and in particular by the thickness and the profile 29 of an internal dagger 32 positioned between the two sides 35, 37. Preferably, the distance separating the two ends of the sidewalls 35, 37 is less than ten millimeters.

In this embodiment and preferably, the flanks 35 and 37 have, at their end, a curvature obtained during the second forming step 42 adapted to fit the profile 29 of the dagger 32.

In both embodiments, the tooling makes it possible to maintain the position of the two sidewalls 35, 37 during the next assembly step.

The shape of the tooling is made to form the contour and the desired intrados and extrados profile of the metal reinforcement 30.

FIG. 9 illustrates an exploded view of the specific holding tooling 60 used for producing the leading edge metal reinforcement according to the embodiment method illustrated in FIG. 3.

The specific tooling of form 60 comprises:

a base 61,

- A first left lateral post 62 secured to the base 61 by screwing means (not shown);

- A second right lateral upright 63 secured to the base 61 by screwing means (not shown), the base 61 having oblong holes 64 so as to modify the position of the right lateral upright 63 by sliding in a direction parallel to the base 61, when the screwing means are not clamped,

- and possibly an internal dagger 32.

During the third positioning step 44, the two flanks 35, 37 are positioned in the specific holding tool 60 so that the two flanks 35, 37 have a common area in contact or the two flanks 35. , 37 are separated by a distance defined by the tool 60. The right lateral upright 63 is positioned by sliding so as to grip the assembly formed by the flanks 35, 37 and possibly the dagger 32. Once in position, the right lateral amount 63 is clamped in position by the screwing means.

The fourth step 46 of the production method 100 is a step of building the base 39 of the reinforcement 30 by a massive reloading of material (or filler metal), by means of a method of arc welding of the MIG type (for "Metal Inert Gas") pulsed current and pulsed filler wire flow rate. Welding is performed at the end of the two sides 35, 37, in particular at the joint area of the two sides 35, 37 referenced 28 in Figures 4 and 5 forming a preform 26 adapted to receive the filler metal.

The MIG welding process makes it possible to construct parts of parts thanks to a high deposition rate in the form of cords of large sections. The length and the width of the recharging cords being defined by the operator according to the flow of the wire.

The step of building the base 39 makes it possible to secure the flanks 35, 37 in position on the tooling 60.

The reloading of material is carried out by superposing cords of metallic material 38 (or of filler metal), of large sections, on the preform 26 and more precisely at the junction of the two flanks 35, 37 in the zone referenced 28. number of passes, that is to say the number of strands of material 38 to be applied, is determined according to the desired material height and the width of the defined strings.

This fourth step 46 of the production method 100 is shown particularly in FIG. 6. Indeed, FIG. 6 illustrates a sectional view of the structural reinforcement 30 in progress after the step of reloading material at the end of the two sidewalls. , 17.

According to the first embodiment in which the flanks 35 and 37 are contiguous in the tooling 60, the internal profile 33 of the base 39 is approximated in bevel by the docking of the two flanks 35, 37 previously shaped during the second step 42.

According to the second embodiment in which the flanks 35, 37 are spaced apart by the dagger 32 of the tooling 60, the internal profile 33 of the base 39 is molded onto the dagger 32. The metal provided by the reloading ensures the junction between the ends of the two flanks 35, 37 and generates the internal profile 33 of the base 39 of the reinforcement 30.

The specific tooling 60 makes it possible to hold the flanks 35, 37 in position during the reloading of material by imprisoning the flanks 35, 37.

The tooling 60 is sufficiently thick to allow the dissipation of the energy provided by the MIG process so that the flanks 35, 37 do not melt and do not deform during the assembly step and / or material reloading. For this purpose, the tool 60 is preferably made of copper or an alloy based on copper and aluminum.

In the second embodiment, the heat dissipation is also performed by the central dagger 32 of the tool 60, preferably made of copper or a copper-aluminum alloy.

The dagger 32 comprises an outer profile 29 able to preform the internal part of each sidewall 35, 37 of the reinforcement 30 and in particular the radiating internal profile 33.

The fifth step 50 of the production method 100 is a machining step of the recharged zone. This step 50 is illustrated in FIG. 7.

This step makes it possible to machine the solid part 27 of material reloaded so as to give it an approximate shape of the final profile of the base 39 comprising the leading edge 31.

The sixth step 52 of the embodiment method 100 is a heat treatment step of stress relieving, or relaxation, of the assembly for relaxing the residual stresses. This heat treatment step is preferably performed in the same specific holding tool 60 which is put in an oven at the forging temperature of the material used. The seventh step 54 of the production method 100 is a hot shaping step preferably carried out in the same specific holding tool 60. This hot shaping step makes it possible to give the desired final shape to the reinforcement 30.

According to a preferred embodiment of the invention, the sixth step 52 and the seventh step 54 are performed at the same time.

It will be recalled that the shape of the tool 60, and particularly the profile of the dagger 32 and the profile of the right lateral post 63 and of the left lateral post 62, are directly related to the final shape and the curve of the desired metal reinforcement 30.

According to another embodiment, the sixth step 52 and the seventh step 54 are performed by means of specific tools for stress relief and conformation able to withstand a rise in temperature. In this case, the production method according to the invention comprises an intermediate step consisting in unclamping the assembly formed by the flanks 35, 37 and the reloaded zone 27 of the specific holding tool 60 in order to be clamped again on the specific tools of stress relief and conformation.

The eighth step 56 of the production method 100 is a finishing step and recovery of the reinforcement 30 by machining. This recovery step 56 comprises:

a first substep 55 of recovery of the profile of the base 39 of the reinforcement 30 so as to refine it and in particular the aerodynamic profile of the leading edge 31;

a second substep 57 of recovery of the flanks 35, 37; this step consisting in particular of trimming the flanks 35, 37 and the thinning of the intrados and extrados flanks;

a third sub-step 59 of finishing making it possible to obtain the required surface state. FIG. 8 illustrates the reinforcement 30 in its final state obtained by the embodiment method according to the invention.

In association with these main production steps, the method according to the invention may also comprise non-destructive testing steps of the reinforcement 30 making it possible to ensure the geometrical and metallurgical conformity of the assembly obtained. By way of example, the non-destructive tests can be carried out by an X-ray method.

According to a second embodiment of the invention, the first step 40 for cutting two flanks, the second step 42 for shaping the two flanks and the third step for positioning the cut flanks 44 may be replaced by a step 41 of FIG. hot forming a preform 70 in a form tooling 80.

This hot forming step 41 is illustrated in FIGS. 10 and 11. In this step, the preform 70 is formed from a flat sheet 71 placed in the form tool 80 which is sealed. The tooling 80 comprises a lower part 82 having an imprint 83 corresponding to the desired shape of the preform 70 and an upper part 81 covering the lower part 82. In its initial state, the flat sheet 71 is held flanged at its ends between the two parts 81, 82 of the tooling 80. The hot forming step is to use the property of metals that have a capacity to deform without breaking at a given temperature, such as aluminum or titanium. By way of example, titanium under certain temperature conditions, for example at 940 ° C., has an elongation rate of greater than 35%.

By way of example, a hot forming process used for this step may be a superplastic forming process (SPF for Super Plastic Forming in English).

Superplastic forming is a process for producing complex sheet metal parts with small thicknesses and in a single surgery.

For the implementation of this method, the sheet 71 is heated to a given temperature, for example at a temperature equivalent to half the melting temperature of the material. At this temperature, the sheet 71 is deformed by the pressure of a neutral gas, for example argon, introduced inside the tool 80 closed. The evolution of this gas pressure, represented by arrows in FIG. 11, is controlled so that the shaping of the sheet 71 takes place in the superplastic domain which is associated with a specific deformation speed range. each family of material. In a known manner, the prediction of the law of evolution of the forming pressure is carried out by numerical simulation so as to optimize the shaping and the cycle time of such a method.

When the preform 70 is formed, it comprises in a manner similar to the previous embodiment, flanks 35, 37 interconnected by an end 72 adapted to receive filler metal. The preform 70 is then demolded from the tool 80 so as to undergo an operation to increase the roughness of the inner faces of the sidewalls 35, 37 in order to increase the adhesion of the preform 70 in the tooling 60 when the step of reloading material and facilitate the attachment of the reinforcement 30 on the blade 10.

After demolding and increasing the roughness of the inner faces of the flanks 35, 37, the fourth step 46 of construction of the base 39 of the reinforcement 30 allows a massive reloading of material (or filler metal), by means of a method arc welding type MIG (for "Metal Inert Gas") pulsed current and pulsed filler wire flow.

The material is reloaded at the end 72 of the preform 70.

As previously described, the MIG welding process makes it possible to construct parts of parts by virtue of a high deposition rate under the form of cords of important sections. The length and the width of the recharging cords being defined by the operator according to the flow of the wire.

The process according to the invention has been described mainly for a titanium-based metal structural reinforcement; however, the process according to the invention is also applicable with nickel-based or steel-based materials.

The use of a MIG type welding process makes it possible to obtain, by a welding process, the structural and mechanical characteristics of a material obtained by casting or forging. Indeed, the welded connection obtained by the MIG process has the same mechanical characteristics as the wrought material.

The invention has been particularly described with a MIG type welding process, however, the MIG welding process can be replaced by another type of material reloading process such as a powder coating process (Laser Cladding type). English language), making it possible to obtain characteristics close to a wrought material.

The invention has been particularly described for producing a metal reinforcement of a composite turbomachine blade; however, the invention is also applicable for producing a metal reinforcement of a turbomachine metal blade.

The invention has been particularly described for producing a metal reinforcement of a turbomachine blade leading edge; however, the invention is also applicable for producing a metal reinforcement of a trailing edge of a turbomachine blade.

Other advantages of the invention include the following:

- reduction of implementation costs;

- reduction of the production time;

- simplification of the manufacturing range; - reduction of material costs.

FIGS. 12 to 21 describe a second method for producing a leading edge or trailing edge metal reinforcement of a turbomachine blade comprising successively:

a step of positioning a first metal sheet and a second metal sheet on a profile by means of a specific tool positioning said profile and said metal sheets so that each metal sheet has a contact surface positioned parallel to a contact surface of said profile;

a soldering step without filler metal of said metal sheets on said profile so that said contact surface of said first metal sheet is integral with said contact surface of said profile and that said contact surface of said second metal sheet is integral with of said contact surface of said profile.

Thanks to this second method, the metal structural reinforcement is made simply and quickly from two flat metal sheets, a standard commercial profile and a welding process without the use of a filler metal. .

This manufacturing method thus makes it possible to dispense with the complex implementation of the reinforcement by milling in the mass from one-piece flats requiring large volumes of processing material and therefore significant costs in supply of raw material.

Indeed, the cost of obtaining a leading edge metal reinforcement or turbomachine blade trailing edge is particularly reduced, in particular by reducing the volume of material necessary for carrying out the reinforcement, by supplying standard form of trade (bars, sheets) and by the use of inexpensive industrial processes of implementation. The welding without the use of a filler metal makes it possible to obtain a weld zone having mechanical characteristics identical to the wrought or forged material and with a very short welding cycle time.

According to an advantageous embodiment, the two metal sheets are welded simultaneously on the profile. The simultaneous welding of the two metal sheets on the profile makes it possible in particular to facilitate the process of holding the metal sheets and makes it possible to obtain the same material removal for each of the sheets, the removal of material resulting from the formation of the welding beads.

The second method of producing a turbomachine blade metal reinforcement may also have one or more of the following characteristics, considered individually or in any technically possible combination:

said metal sheets are welded simultaneously to said profile; said step of welding said metal sheets to said profile is carried out by means of a linear friction welding method;

said step of welding said metal sheets to said profile is carried out by means of a resistance welding method or by a flash-welding method;

said positioning step is preceded by a step of forming and / or bending the profile and / or said metal sheets;

- Said welding step is followed by a shaving step by machining the welding beads and / or shelving of said profile so as to form the internal profile of said metal reinforcement;

the method comprises a hot conformation step in a hot conformation tool comprising a central dagger adapted to shape the profile of said metal sheets, said dagger extending beyond the solder joints formed during said welding step; , so as to avoid the deformation of said solder joints during said hot conformation step;

the method comprises a stress relaxation heat treatment step;

the method comprises a step of finishing said metal reinforcement consisting of:

- A substep of mechanical recovery in milling said profile so as to achieve the aerodynamic profile of the leading edge, or the trailing edge, and the base of the reinforcement:

a substep of cutting said metal sheets so as to obtain the sidewalls of the reinforcement;

a sub-step of polishing the surface of said metal sheets;

- The method comprises a step of cutting said first metal sheet and said second metal sheet by a cutting process and / or machining said profile by a milling or rolling process.

The second embodiment also makes it possible to produce a structural reinforcement as illustrated in FIG. 2, FIG. 2 illustrating the reinforcement 30 in its final state.

Fig. 12 is a block diagram illustrating the main steps of the second method of making a blade blade leading edge metal structural reinforcement 10 as illustrated in Figs. 1 and 2.

The first step 1 10 of the production method 200 is illustrated in FIG. 13 and corresponds to a step of cutting plane sheets 141, 142 and machining a profile 144.

The plane sheets 141, 142 are cut from standard commercial sheets according to a specific profile 143 corresponding to an approximate profile of the longitudinal shape of the leading edge 16 of the blade 10.

The plane sheets 141, 142 are cut by a method of cutting known to those skilled in the art for cutting sheets of small thickness, that is to say of the order of a few millimeters. For example, the cutting method may be a laser cutting method or a method of cutting by water jet or by punching.

The two cut sheets 141, 142 are intended to form the two sidewalls 35, 37, intrados and extrados of the metal reinforcement 30 illustrated in FIG.

The section 144 is produced in a conventional manner, for example by a rolling or milling process from a standard bar of material. The profile 144 can also be produced by extrusion and milling of a standard profile. The profile 144 is a blank for forming the base 39 of the reinforcement 30 illustrated in FIG.

The machined profile 144 is a rectilinear profile of prismatic shape and whose upper face 145 comprises a longitudinal groove 148 and a first portion 146 and a second portion 147 protruding on either side of the groove 148.

The second step 120 of the production method 200 is a step of forming and / or bending of the section 144 and possibly cut sheets 141, 142. The bending is carried out by a stressing of the section 144 and / or sheets 141, 142, for example by means of a press.

The cambered profile 144 and the cut sheets 141, 142 are illustrated in FIG. 14. It will be noted that the bending of the section 144 is determined so as to match the specific profile 143 of the cut sheets 141, 142 and so as to obtain substantially the shape definitive edge of attack 16 dawn 10.

According to a first embodiment of the second embodiment method, the bending of the section 144, and possibly sheets 141, 142, is made in two dimensions. However, it is also conceivable to camber the profile 144 directly in three dimensions as well as sheets 141, 142.

The third step 130 of the production method 200 is a step of positioning, or docking, the two cut sheets 141, 142 on the section 144. This step notably allows the positioning of the contact surface 149 of each cut sheet 141, 142 on the upper surface of each portion 146, 147 of the profile 144.

For this purpose, the two sheets 141, 142 and the section 144 are positioned in a specific tool 160 capable of maintaining the assembly, particularly during the next welding step. This third step 130 is illustrated in Figure 15a and Figure 15b. FIG. 15a illustrates more particularly a side view of the positioning of the two cut sheets 141, 142 on the section 144 and FIG. 15b more particularly illustrates a section of FIG. 15a according to a section plane C-C illustrated in FIG. 15a.

The two cut sheets 141, 142 are respectively positioned facing a projecting portion 146, 147 of the profile 144.

FIG. 21 illustrates a cross-sectional view of an example of holding tooling 160 holding in position the cut sheets 141, 142 and the section 144.

The specific maintenance tooling 160 comprises:

an upper cassette 171 comprising an upper insert 172;

a lower cassette 161 comprising a lower insert 162.

The lower insert 162 includes a recess 169 adapted to receive the profile 144. The profile 144 is clamped in the lower insert 162 in position by means of screwing means 163 along the entire length of the profile 144. For this purpose, the profile 144 is dimensioned to have sufficient material for clamping into the lower insert 162.

The cut sheets 141, 142 are held in position in the upper insert 172 of the tooling 160. For this purpose, the upper insert 172 is formed by an upper sole 173 comprising a central element 175 of shape. prismatic protruding from the plane of joint 170 of the upper flange 173 and the lower flange 174. The lower flange 174 is formed by two parts 174a and 174b which come to press the plates 141, 142 in position against the side walls of the flange. central element 175 during the clamping of the upper sole 173 and the lower sole 174. The clamping of the assembly is performed by screwing means 176.

The fourth step 140 of the production method 200 is a step of welding the sheets 141, 142 on the section 144 without the addition of a filler metal. According to a first embodiment, the welding method is a linear friction welding method. The linear friction welding is performed by means of the specific holding tool 160 which is mounted on an oscillating table (not shown).

Friction welding is a mechanical welding process where the heat required for welding is provided by friction, or rotation in the case of an orbital friction process, of a first piece against a second piece, both pieces to be assembled being subjected to opposite axial pressure.

The friction is achieved by the oscillation of a room while the other room is held fixed. According to an advantageous embodiment, the lower insert 162 clamping the profile 144 is held stationary while the upper insert 172 clamping the sheets 141, 142 oscillates in a direction parallel to the joint plane 170.

When the two sheets 141, 142 simultaneously come into contact, at their contact surface 149, with the projecting portions 146, 147 of the section 144, by progressively bringing the upper cassette 171 and the lower cassette 161 closer together, the forces friction causes a couple of resistance. The created mechanical energy is transformed into heat in the contact surface increasing the temperature rapidly up to the welding temperature (forging temperature of the materials used). During the heating and welding phase, a quantity of material is pushed outwards thus forming welding beads 151 and a shortening of the moving parts. This step is illustrated in FIG. 16. FIG. 16 more particularly illustrates a view of the two plates 141, 142 welded by linear friction on the section 144.

The tool 160 is used to weld by linear friction the two sheets 141, 142 simultaneously on the section 144 while positioning the friction surfaces of the sheets 141, 142 and the section 144 parallel. That is to say that during the linear friction welding step, each contact surface 149 of the two metal sheets 141, 142 is parallel to a contact surface of the portions 146, 147 of the profile 144.

The simultaneous welding of the two sheets 141, 142 makes it possible in particular to facilitate the process of holding the sheets 141, 142 and makes it possible to obtain the same material withdrawal for each of the sheets 141, 142, the removal of material resulting from the formation of the beads. welding 151.

According to the embodiment illustrated in FIG. 21, the two metal sheets 141, 142 are V-welded to the section 144. According to a second embodiment, not shown, the two metal sheets 141, 142 can be welded in parallel on the profile. 144.

Linear friction welding provides the same mechanical characteristics as wrought or forged material and with a very short welding cycle time.

The fifth step 150 is a step of shaving the welding beads 151 by machining and racking the groove 148 so as to form the internal profile 33 of the final metal reinforcement 30. This fourth step is illustrated in FIG. 17. The internal profile 33 corresponds to the profile of the metal reinforcement 30 in its final state and is defined so as to optimize the distribution of the stresses in the reinforcement.

The sixth step 160 is a hot conformation step to give the final shape to the reinforcement 30. This hot conformation step is performed in a specific tool 180 able to withstand a rise in temperature in an oven at the forging temperature of the material used.

The tooling 180, as illustrated in FIG. 18, is formed by an upper part 181 and a lower part 182 bordering on each side the metal sheets 141, 142 welded to the profile 144 and shaped forming the reinforcement 30. The tooling 180 also comprises a central dagger 183 is able to be inserted between the two sheets 141, 142. The shape of the tool 180 and more particularly the shape of the upper parts 181 and lower 182 and the profile of the dagger 183 correspond to final intrados and extrados profiles of the flanks 35, 37 of the metal reinforcement 30.

The upper parts 181 and lower 182 of the tooling 180 comprise at their internal face, an obviously able to receive and maintain in position the profile 144 during the hot forming step.

Note that the dagger 183 is dimensioned so that the solder joints between the sheets 141, 142 and the section 144, formed during the welding step 140, rest on the dagger 183. In this way, the constraints and the deformations are limited in these areas of welding during the hot conformation. Advantageously, the dagger 183 is inserted between the two sheets 141, 142 so as to marry to the maximum the inner profile of the section 144. For this purpose, the dagger 183 is adapted according to the internal profile 33 defined and has a complementary shape internal profile 33.

During this conformation step, the specific tooling 180 is placed in an oven at the forging temperature of the material used. This heat treatment also relaxes the residual stresses of the assembly. The seventh step 170 is a finishing and mechanical recovery step illustrated in FIG. 19. This step comprises a first substep of mechanical recovery in milling of the profile 144 so as to produce the aerodynamic profile of the leading edge 31 as well as the base 39 of the reinforcement 30 shown in Figures 2 and 20. A second substep consists of cutting and trimming the sheets 141, 142 welded and shaped so as to obtain the sidewalls 35, 37 of the final reinforcement 30. This sixth step 160 also comprises a sub-step of polishing the sheets 141, 142 so as to obtain the required surface state and the thicknesses of the desired sidewalls 35, 37, in particular at the level of the thin parts intended to wrap the composite material of dawn 10.

FIG. 20 is a side view of the reinforcement 30 in its final state obtained by the second method of producing a metal reinforcement.

In association with these main production steps, the second embodiment may also include non-destructive testing steps of the reinforcement 30 to ensure geometric and metallurgical compliance of the assembly obtained. By way of example, the non-destructive tests can be carried out by an X-ray method.

According to a second embodiment of the second embodiment method, the fourth step 140 of welding the sheets 141, 142 on the section 144 is carried out by a spark welding process or resistance welding. Spark welding and resistance welding are two processes that do not require filler metal to weld parts.

Spark welding and resistance welding use the Joule effect due to the passage of low voltage and high current for melting and welding of parts.

In the sputter welding process, the intense current flow, through the asperities distributed on the contact faces between the two pieces, produces arches with ejections and sprays of molten metal outward from the contact faces. As soon as the end of the sparking, a pushing force is applied on the parts to be assembled, pushing back in the form of burr the thin layer of liquid that remains on the contact surface.

In the resistance welding process, the parts to be assembled are clamped in jaws which supply the current. The faces to be assembled must be carefully prepared and free from oxides and scale. As soon as the current passes, the parts heat up and weld by joule effect. A significant effort is exerted during the welding operation so that the metal is forced back. The metal in the plastic state forms a bead on both sides of the joint section.

Spark and resistance welding make it possible to obtain mechanical characteristics identical to wrought or forged material and with a very short welding cycle time.

According to an advantageous embodiment of the second embodiment method, the two sheets 141, 142 are welded simultaneously on the section 144.

The second production method has been described mainly for a titanium-based metal structural reinforcement; however, the second embodiment is also applicable with nickel-based or steel-based materials.

The second embodiment method has been particularly described for producing a metal reinforcement of a turbomachine composite blade; however, the second embodiment method is also applicable for producing a metal reinforcement of a turbomachine metal blade.

The second embodiment method has been particularly described for producing a metal reinforcement of a turbomachine blade leading edge; however, the second embodiment is also applicable for the realization of a metal reinforcement of a trailing edge of a turbomachine blade.

The other advantages of the second embodiment method include the following:

- reduction of implementation costs;

- reduction of the production time;

- simplification of the manufacturing range;

- reduction of material costs;

- high metallurgical quality of the welded zone.

Claims

Process for producing a metal reinforcement (30) for a leading edge or a turbomachine blade trailing edge successively comprising:

a step (44) for positioning a preform (26, 70) by means of a tool (60) positioning said preform (26, 70) in a position such that said preform (26, 70) presents a end a zone (28, 72) adapted to receive filler metal;

- A step (46) of building a base (39) of said metal reinforcement (30) by reloading filler metal in said zone (28, 72), in the form of metal beads.

A method of producing a turbomachine blade metal reinforcement (30) according to claim 1, characterized in that said step (46) for building by reloading of filler metal is carried out by means of a MIG welding apparatus comprising a pulsed current generator having a flow rate of pulsed filler wire.

Process for producing a turbine engine blade metal reinforcement (30) according to one of Claims 1 to 2, characterized in that the said preform (26) comprises a first metal sheet (35) and a second metal sheet (37). positioned, by means of said tooling (60), in a non-parallel position so that they have at their end a zone (28) capable of receiving said filler metal, said step of constructing said base (39) of said reinforcement (30) solidarisant said metal sheets (35, 37) in position.

4. Process for producing a metal reinforcement (30) of blade of Turbomachine according to one of claims 1 to 2 characterized in that said preform (70) is formed by a hot preformed metal sheet (71) so that said preform (70) has flanks (35, 37) and at a end a zone (72) adapted to receive said filler metal.

Process for producing a turbomachine blade metal reinforcement (30) according to one of Claims 1 to 4, characterized in that said construction step (46) is followed by a machining step (50) of said reloaded material (27) in said welding end region (28) so as to approach the final profile of said base (39).

A method of producing a turbine engine blade metal reinforcement (30) according to claim 5 characterized in that it comprises a step (52) of stress relaxation heat treatment.

A method of producing a turbine engine blade metal reinforcement (30) according to one of claims 5 to 6 characterized in that it comprises a step (54) of hot conformation.

Process for producing a turbine engine blade metal reinforcement (30) according to one of Claims 6 to 7, characterized in that it comprises a step (56) of finishing said metal reinforcement (30) consisting in the recovery of said recharged material (27) so as to refine the final profile of said base (39) and the leading edge (31) or the trailing edge of said metal reinforcement (30) and / or the recovery of the metal sheets (35). , 37) so as to form the flanks of said metal reinforcement (30).

9. A method of producing a metal reinforcement (30) turbomachine blade according to one of claims 1 to 8 characterized in that it comprises a step (40) of cutting said first sheet metal (35) and said second sheet metal (37) by laser cutting.

10. A method of producing a metal reinforcement (30) turbomachine blade according to one of claims 1 to 9 characterized in that it comprises an operation of increasing the roughness of the inner faces of said flanks (35, 37 ).

1 1. Process for producing a turbine engine blade metal reinforcement (30) according to one of Claims 1 to 10, characterized in that it comprises a step (42) for shaping said metal sheets (35, 37) before said positioning step in said tooling (60).

12. A method of producing a metal reinforcement (30) turbomachine blade according to one of claims 1 to 1 1 characterized in that, during said step (44) of positioning, said metal sheets (35, 37 ) are shaped in said tool (60) and are held together.

13. A method of producing a metal reinforcement (30) turbomachine blade according to one of claims 1 to 12 characterized in that, during said step (44) of positioning, said metal sheets (35, 37). are shaped and are kept spaced apart by a dagger (32) positioned between said metal plates (35, 37), the external profile of said dagger (32) conforming the profile of the intrados and the extrados of said metal sheets (35, 37).

14. A method of producing a metal reinforcement (30) turbomachine blade according to one of claims 1 to 13 characterized in that it comprises a step of removing heat from said metal sheets (35, 37). in position in said tooling via said tooling (60).